/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.rop.cst;

import com.android.dx.rop.type.Type;
import com.android.dx.util.Hex;

/**
 * Constants of type {@code CONSTANT_Integer_info}.
 */
public final class CstInteger extends CstLiteral32 {

	/** {@code non-null;} array of cached instances */
	private static final CstInteger[] cache = new CstInteger[511];

	/** {@code non-null;} instance representing {@code -1} */
	public static final CstInteger VALUE_M1 = make(-1);

	/** {@code non-null;} instance representing {@code 0} */
	public static final CstInteger VALUE_0 = make(0);

	/** {@code non-null;} instance representing {@code 1} */
	public static final CstInteger VALUE_1 = make(1);

	/** {@code non-null;} instance representing {@code 2} */
	public static final CstInteger VALUE_2 = make(2);

	/** {@code non-null;} instance representing {@code 3} */
	public static final CstInteger VALUE_3 = make(3);

	/** {@code non-null;} instance representing {@code 4} */
	public static final CstInteger VALUE_4 = make(4);

	/** {@code non-null;} instance representing {@code 5} */
	public static final CstInteger VALUE_5 = make(5);

	/**
	 * Makes an instance for the given value. This may (but does not
	 * necessarily) return an already-allocated instance.
	 * 
	 * @param value
	 *            the {@code int} value
	 * @return {@code non-null;} the appropriate instance
	 */
	public static CstInteger make(int value) {
		/*
		 * Note: No need to synchronize, since we don't make any sort of
		 * guarantee about ==, and it's okay to overwrite existing entries too.
		 */
		int idx = (value & 0x7fffffff) % cache.length;
		CstInteger obj = cache[idx];

		if ((obj != null) && (obj.getValue() == value)) {
			return obj;
		}

		obj = new CstInteger(value);
		cache[idx] = obj;
		return obj;
	}

	/**
	 * Constructs an instance. This constructor is private; use {@link #make}.
	 * 
	 * @param value
	 *            the {@code int} value
	 */
	private CstInteger(int value) {
		super(value);
	}

	/** {@inheritDoc} */
	@Override
	public String toString() {
		int value = getIntBits();
		return "int{0x" + Hex.u4(value) + " / " + value + '}';
	}

	/** {@inheritDoc} */
	public Type getType() {
		return Type.INT;
	}

	/** {@inheritDoc} */
	@Override
	public String typeName() {
		return "int";
	}

	/** {@inheritDoc} */
	public String toHuman() {
		return Integer.toString(getIntBits());
	}

	/**
	 * Gets the {@code int} value.
	 * 
	 * @return the value
	 */
	public int getValue() {
		return getIntBits();
	}
}
